#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

class Solution {
 public:
  bool canMakeArithmeticProgression(vector<int>& arr) {
    sort(arr.begin(), arr.end());
    for (int i = 1; i < arr.size() - 1; i++) {
      if (arr[i + 1] - arr[i] != arr[i] - arr[i - 1]) return false;
    }
    return true;
  }
};
